Junk DNA: goodbye! (Introduction)

by David Turell , Saturday, September 28, 2013, 01:58 (3864 days ago) @ David Turell

ENCODE research has done a major job of chipping away at junk DNA. Junk DNA has been important 'evidence' that chance mutations left behind lots of unnecessary stuff in DNA during all the time of evolution. ENCODE suggested that 80% of DNA has some function. Now a new study using a different type of approch is dicussing the possibility that 95% of DNA is useful:-http://science.psu.edu/news-and-events/2013-news/Pugh9-2013-"A duo of scientists at Penn State University has achieved a major milestone in understanding how genomic "dark matter" originates. This "dark matter" -- called non-coding RNA -- does not contain the blueprint for making proteins and yet it comprises more than 95 percent of the human genome. The researchers have discovered that essentially all coding and non-coding RNA originates at the same types of locations along the human genome. The team's findings eventually may help to pinpoint exactly where complex-disease traits reside, since the genetic origins of many diseases reside outside of the coding region of the genome."-"Pugh added that it was easy to dismiss these fragments because they lacked a feature called polyadenylation -- a long string of genetic material, adenosine bases -- that protect the RNA from being destroyed. Pugh and Venters further validated their surprising findings by determining that these non-coding initiation machines recognized the same DNA sequences as the ones at coding genes, indicating that they have a specific origin and that their production is regulated, just like it is at coding genes.
 
"These non-coding RNAs have been called the 'dark matter' of the genome because, just like the dark matter of the universe, they are massive in terms of coverage -- making up over 95 percent of the human genome. However, they are difficult to detect and no one knows exactly what they all are doing or why they are there," Pugh said. "Now at least we know that they are real, and not just 'noise' or 'junk.' Of course, the next step is to answer the question, 'what, in fact, do they do?'"